Question 242728
after 30 min, the tank is 3/4 full (30/40); so the two pipes only have to fill 1/4 of the tank


let x="remaining minutes to fill"


x/40 + x/25 = 1/4


multiplying by 200 (LCD) ___ 5x + 8x = 50


13x = 50 ___ x = 50/13 (a little less than 4 min)